Hello @jmagtags,
Thank you for reaching out!
The manually chosen product block does not allow customizing the size of the letters, nor customizing the CSS with external CSS.
Just to confirm, are you referring to the Single Product block?
I’m able to customize the title and assign it a dedicated CSS class without any problem. Please check the screencast below.
Link to image: https://d.pr/i/cfDysI
Could you please attach a few screenshots of what you’re seeing from your end? :?)
If you don’t already have a screenshot service installed, here are a few free options:
It would be great if you could attach a copy of your system status as well. You can find it via WooCommerce > Status. Select “Get system report” and then “Copy for support” (after you scroll down a bit)”. Once done, please paste it here in your reply or via a text-sharing service like https://gist.github.com/.
Look forward to hearing back from you.